Modular double brazed phase-change material heat exchanger

Abstract

A phase change material (PCM) heat exchanger system for a rocket or other spacecraft is described. The PCM heat exchanger utilizes phase-change material to store heat absorbed from a hot working fluid. The PCM heat exchanger may be configured as an integrated modular double brazed layout that includes folded fins to distribute heat from a working fluid (e.g., hydraulic fluid) to PCM. A modular configuration may enable a heat exchanger system to be scaled up or down by adding or removing modules to meet cooling requirements for particular rockets and their flights.

We claim as follows: 
     
         1 . A heat exchanger system for a rocket, the heat exchanger system comprising:
 a heat exchange component configured to carry a working fluid;   a phase change material (PCM) component comprising PCM, wherein the PCM component is in thermal contact with the heat exchange component; and   a working-fluid supply system configured to provide the working fluid to the heat exchange component such that the working fluid is i) hotter than the melting temperature of the PCM during flight of the rocket and ii) colder than the melting temperature of the PCM when the rocket is stationary on a launch pad for the rocket.   
     
     
         2 . The heat exchanger system of  claim 1 , wherein the PCM component comprises a support matrix having a network of cavities at least partially filled with the PCM. 
     
     
         3 . The heat exchanger system of  claim 2 , wherein the support matrix has a honeycomb structure. 
     
     
         4 . The heat exchanger system of  claim 2 , wherein the support matrix is a lanced offset fin structure. 
     
     
         5 . The heat exchanger system of  claim 1 , wherein the working fluid is a hydraulic oil. 
     
     
         6 . The heat exchanger system of  claim 1 , wherein the working fluid supply system comprises valves that operate to select either the working fluid that is hotter than the melting temperature of the PCM or the working fluid that is colder than the melting temperature of the PCM. 
     
     
         7 . The heat exchanger system of  claim 6 , wherein the selection by the valves is based, at least in part, on a determination of location of the rocket. 
     
     
         8 . The heat exchanger system of  claim 1 , further comprising lanced offset heat fins between the heat exchange component and the PCM component. 
     
     
         9 . The heat exchanger system of  claim 1 , wherein the heat exchange component comprises serpentine-shaped chambers to carry the working fluid. 
     
     
         10 . A heat exchanger for a rocket, the heat exchanger comprising:
 a heat exchange component configured to carry a working fluid; and   a phase change material (PCM) component comprising PCM, wherein
 the PCM component is in thermal contact with the heat exchange component, and 
 the PCM component comprises a lanced offset fin structure having a network of cavities at least partially filled with the PCM. 
   
     
     
         11 . The heat exchanger of  claim 10 , further comprising a working-fluid supply system configured to provide the working fluid to the heat exchange component such that the working fluid is i) hotter than the melting temperature of the PCM during flight of the rocket and ii) colder than the melting temperature of the PCM when the rocket is stationary on a launch pad for the rocket. 
     
     
         12 . The heat exchanger of  claim 11 , wherein the working-fluid supply system comprises valves that operate to select either the working fluid that is hotter than the melting temperature of the PCM or the working fluid that is colder than the melting temperature of the PCM. 
     
     
         13 . The heat exchanger of  claim 12 , wherein the selection by the valves is based, at least in part, on a determination of location of the rocket. 
     
     
         14 . The heat exchanger of  claim 10 , wherein the PCM component is a first PCM component and the heat exchanger further comprises a second PCM component, wherein the first PCM component, the heat exchanger component, and the second PCM component are mutually assembled by double brazing. 
     
     
         15 . The heat exchanger of  claim 10 , further comprising lanced offset heat fins between the heat exchange component and the PCM component. 
     
     
         16 . A method of operating a heat exchanger in a rocket, the method comprising:
 conveying working fluid through a heat exchange component that is in thermal contact with a phase change material (PCM) component comprising PCM; and   providing the working fluid to the heat exchange component such that the working fluid is i) hotter than the melting temperature of the PCM during flight of the rocket and ii) colder than the melting temperature of the PCM when the rocket is stationary on a launch pad for the rocket.   
     
     
         17 . The method of  claim 16 , wherein the PCM component comprises a lanced offset fin structure having a network of cavities at least partially filled with the PCM. 
     
     
         18 . The method of  claim 16 , further comprising:
 determining a location of the rocket; and   selecting, based at least in part on the determined location of the rocket, either the working fluid that is hotter than the melting temperature of the PCM or the working fluid that is colder than the melting temperature of the PCM.   
     
     
         19 . The method of  claim 16 , further comprising:
 measuring a temperature difference between the working fluid entering the heat exchange component and the working fluid exiting the heat exchange component; and   determining, based on the measured temperature difference, a phase of the PCM.   
     
     
         20 . The method of  claim 19 , further comprising selecting, based at least in part on the determined phase, either the working fluid that is hotter than the melting temperature of the PCM or the working fluid that is colder than the melting temperature of the PCM.